Electric speedometer



Nov. 3, 1953 w. M CANDLESS 2,657,919

ELECTRIC SPEIEIDOMETER Original Filed July 25, 1947 3 Sheets-Sheet 1 INV EN TOR. Mum/w fl-(emm Nov. 3, 1953 w, MGCANDLESS 2,657,919

ELECTRIC SPEEDOMETER Ofiginal Filed July 25, 1947 5 Sheets-Sheet 2ATTORNEYS Nov. 3, 1953 w. M CANDLESS 7,

ELECTRIC SPEEDOMETER Original Filed July 25, 1947 3 Sheets-Sheet 3 I N VEN TOR. Mum/ M M01 63 BY 0 mmmlz ATTORNEYS Patented Nov. 3, 1953ELECTRIC SPEEDOMETER William McCandless, Toledo, Ohio Originalapplication July 25, 1947, Serial No.

763,546, now Patent No. 2,523,993, dated September 26, 1950. Divided andthis application March 25, 1949, Serial No. 83,327

Claims.

This invention relates to speedometers, more particularly to aspeedometer of an electrical type which is adapted to be installed asoriginal factory equipment on automotive vehicles regardless of theposition of the engine thereof or the position of the moving element ofthe vehicle from which the speed indications are initiated, or theposition of the station to which the speed indications are transmittedand displayed to the operator.

The invention contemplates the provision of an improved electricalspeedometer device which is energized from a direct current source by aninitiating or translating device which cooperates with a moving part ofthe vehicle to translate the direct current into polyphase alternatingcurrents which are transmitted to the receiving end where the polyphasealternating currents are utilized to drive an electric motor. Theelectric motor, in turn, drives the rotating magnets of an eddy currentspeed cup device which moves an indicating pointer in a measure having arelation to the speed of the moving part of the vehicle which initiatedthe polyphase alternating currents driving the electric motor.

The invention further contemplates providing an electrical speedometerdevice which obviates the use of contact points for telemetering, to adistant point, information relating to the speed and to the distancetraversed by the vehicle to which the device is attached.

The invention further contemplates the provision of an electricalspeedometer device utilizing polyphase currents to drive an electricmotor which will indicate both the speed of the vehicle and also thedistance traversed by the vehicle.

The invention further contemplates the provision of a novel mounting andbearing means for the indicating pointer, whereby fluttering of theindicating pointer is obviated, due to eccentricities and yet which willmove in such a manner as to give an operator the impression that thepointer is operative without undue fluttering or sticking duringoperation.

The invention further contemplates providing a construction of anelectrical speedometer which is rugged and which is suitable for massproducticn.

It is, therefore, a principal object of this invention to provideanimproved electrical speedometer which utilizes polyphase alternatingcurrents from translated direct current, in which the poiyphascalternating currents are utilized to drive an electric motor, whichwill, in turn, drive devices indicating speed an also distance traversedby-the vehicle.

It is a further object of this invention to provide a novel shaftsuspension for an indicating pointer of a speedometer device which willprevent excessive fluttering thereof and yet will have suificientmovement to give the impression to an operator that the pointer is notstuck.

It is a further object of this invention to provide mechanicalimprovements of speedometer devices which will facilitate itsfabrication in a mass production line and which will be rugged underservice conditions.

Other objects and advantages of this invention relating to thearrangement, operation and function of the related elements of thestructure, to various details of construction, to combinations of partsand to economics of manufacture, will be apparent to those skilled inthe art upon consideration of the following description and appendedclaims, reference being had to the accompanying drawings forming a partof this specification wherein like reference characters designatecorresponding parts in the several views.

Referring to the drawings:

Fig. 1 is an elevational view of an apparatus incorporating theinvention;

Fig. 2 is an elevational view of the face of the indicating device;

Fig. 3 is an elevational view, partly in section, taken along line 3-3of Fig. 1;

Fig. 4 is an elevational View, in section, of the indicating devicetaken along line 4-4 of Fig. 3;

Fig. 5 is a plan View, in section, taken along line 55 of Fig. 3;

Fig. 6 is an elevational view, partly in section, of themotormecha-nism;

Fig. 7 is an elevational view, partly in section, ofthe odometer geartrain;

Fig. 8 is an elevational view, partly in section, of the odometer train;

Fig. 9 is an isometric view of one of the parts; and

Fig. 10 is a plan View, partly in section, of the zero point stop.

Reference is made to Patent No, 2,523,993, issued September 26, 1950,maturing from application, Serial No. 763,546, filed July 25, 1947, of

which this application is a division.

Referring to the drawings, particularly to Fig.

1, an initiating device or translator 30 is shown cooperating with areceiver or indicating device 32 and interconnected therewith byelectrical conductors 3E, 36, and 38. Electrical energy is supplied tothe initiating device 39 by a storage battery it of the motor vehicle,to which the electrical speedometer of the invention is attached, and isconnected thereto by means of conductor 42 which is controlled by amanual switch. 44 such as, for example, the ignition switch of the vehicle. One side of the battery it is grounded at 48 and the circuit iscompleted by grounding the casing of the initiating device as shown.

The moving part or rotor of the initiating device 3!! is rotated bymeans of a flexible cable 50, operatively connected thereto, one end ofwhich is connected to the rotor and the other end to a moving part 48 ofthe vehicle which rotates in a proportional relationship to the groundspeed of the vehicle. The driving connections between the rotor and themoving part 48 of the vehicle may comp-rise a flexible cable such aspresently used in connection with speedometers of automotive vehiclesand, being well known in the art, need not be described in furtherdetail herein.

Referring again to Fig. 1, the leads 34, 36, and 38, which carrypolyphase A. C. currents, are connected to an indicating device 2% whichconsists generally of an alternating current motor 202 (Fig. l), whichdrives, by means of a shaft 284, a permanent magnet 226 of aneddy-current speedometer device which has a speed cup 208 and a fieldmember 2). The speed cup is connected to a shaft 212, journaled in aspecial bearing sleeve 2l i, to be described in further detailhereinafter, to drive a pointer Zlt, which cooperates with a dial member2 It, to indicate to an observer the desired indications of miles perhour through a transparent glass face 220, as is best shown in Fig. 2,which shows the pointer and dial as seen by an observer.

Returning again to the shaft 202-, which is driven by the electric motor202, a worm 222 is connected thereto directly behind the permanentmagnet 206 to drive, by means of a cooperating gear 22 spindle member226 (Fig. '7), which is provided with a worm 228 to cooperate with asecond gear 23% on spindle 232. The spindle 232 (Fig. 8) is similarlyprovided with a worm 234 which is utilized to drive, by means ofsuitable gear 236 of an odometer 233, best seen in Fig. 3 and observablethrough windows 240 provided in the dial 2I8. A pair of odometers may beprovided, if desired, both being driven by the same gear train, alreadydescribed, by other suitable gearing well known in the art which neednot be described in further detail.

The odometers are mounted on shafts 242 and 244 in aligned parallelrelation with the faceplate or dial 218, so that the indexes on theperipheries of the individual odometer wheels may clearly be seen by anobserver through the windows 2% and 241 provided adjacent their forwardportions. The construction of the odometers and their operation withreference to the present invention are well known in th art and will notbe described in further detail. A novel holding means, however, isprovided to cooperate with the shafts 242 and 224 to hold the shafts infixed rotatable relation with a frame member which will be described ingreater detail hereinafter.

Turning now to the motor 2532, the three leads 34, 36, and 38 cooperatewith terminals 258, 252, and 254, as shown in Fig. 6. The terminals aremounted sockets in an insulated cup 255, as is best shown in Fig. 4,where only the terminal 250 is shown in a sectional View. The threephasecurrents which are introduced in the motor casing by these terminals areconnected by leads such as 256 and 25? to the field coils 2% of theelectric motor, being mounted in an annular laminated iron fieldstructure 2552 having D shoes 262A, as is best shown in Fig. 6. Thefield structure 2'62 is circular in exterior form and is held inposition by recesses 263 and 254 in the insulating cup 255 and a framemember 265 re spectively, all being held in assembled relation by bolts256 threaded into the frame member shown. A spacer ring 255A may beprovided if desired. The field coils 2% may be connected in either Y ordelta.

The three pole shoes create a rotating field by the three-phasealternating current which acts upon an armature 261, preferably apermanent magnet and may be of unitary or of laminated construction, asshown in Fig. 4. The permanent magnet of the armature 25: is preferablyin the form of a truncated cylinder, as shown in Fig. 6, or, if desired,it may be left in the form of a simple cylinder, and is stronglymagnetized. as to be polarized, so that it will rotate in syn chronismwith the rotating field. created by the field coils 252.

The armature 261 of the motor 282 is fixedly attached to shaft 284 whichis journaled in a bearing sleeve 2'68 fixed centrally in frame member265, shown in section in Fig. 4, being provided with convenient oilingarrangements 21!}, as is well known in the art. As has been alreadydescribed, the armature shaft 204 rotates the U-- shaped permanentmagnet 286 which is fixedly attached to the opposite end of the shaft2%. The magnet 29B is provided With a magnetic temperature compensator212 on the rear face thereof, so that its field strength will remainsubstantially constant through temperature variations. As the magnet 206is rotated by the armature 251 of the motor 202, it drags with it thespeed cup 265 through the action of the magnetic flux of the magnet 20%cooperating with the fixed field member 212, against the bias of thehair spring 212 acting on the shaft 212 carrying the speed cup andpointer 2H3 as already described.

The polyphase alternating current created by the initiating device 30creates a rotating field in the electric motor 202 which causes thearmature 26'! (permanent magnet) to rotate in synchronism therewith,whereby a predetermined relation is established between the rotation ofthe shaft 56 in the initiating device 30 and the rotation of thearmature 231 of the motor 292. This pre determined relation is dependentupon the norm ber of poles provided in the field member of the motor 202and may vary, which, however, in the particular construction describedherein, the shaft 54 and the shaft 284-, rotate at the same speed in theinitiating mechanism and the indicating mechanism respectively. Theshaft 264 rotates the permanent magnet 266 and drags with it the eddycurrent speed cup 298 and thereby causes an angular rotation of theshaft 2l2, as indicated by the pointer 2H5 to create a balance betweenthe magnetic drag on the speed cup 268 and the bias of hair spring 214.As the permanent magnet 286 is rotated at a higher rate, the angulardisplacement of the pointer 216, with reference to dial plate 218, willbe increased until it is balanced by the displacement of the hair spring214. This gives the desired indication by observing the relation betweenthe pointer 216 and the dial 2l8. As the speed is retarded, the hairspring 214 returns the pointer toward the zero mark, which will beattained at the termination of rotation of the armature 261.

In order to support the field member 21!} in concentric relation withthe rotating magnet 206 and the eddy current speed cup 298, a hollowboss 226 is provided on the forward face of the frame member 265, beingconcentric with the; shaft 204 and 212, as. is most clearly shown in.Fig. 4; The. boss are terminates adjacent the rear face of, the magnetictemperature compensator 212. and is provided with an annular boss 278which cooperates with the lip of the cup-like elementEi E to form acentering attachment therefor. The speed cup are is held on the boss 218by means of a coil spring 280 embracing the hearing sleeve 2M which isfixedly attached to a bridge member 282 supported by a, pair ofabutments 284 and 285 extending from the forward face of the framemember 2&5, as is most clearly shown in Figs. 4 and 5. The bridge member282 is held against the ends of the abutments 284 and 236 by means ofscrews 288 threaded into the forward face of the abutments.

The bearing sleeve 2M, which supports and guides the spring member 289upon its exterior, and also performs the function of journalling theshaft M2, which will be described in greater detail hereinafter, isprovided with a threaded portion 253i? adjacent its forward end which isthreaded into an aperture in the bridge member 282 and is adjustablylocked therein by means of a not 252. The sleeve 2M, beinglongitudinally adjustable, predetermines the tension of the coil spring23b which abuts at its outer end against a shoulder 294, preferablyformed at one terminus of a hexagonal portion of the sleeve 254 whichallows convenient manipulation of the sleeve by a tool such as a wrench.lhe inner end of the sleeve 2M cooperates with a centrally-locatedaperture 295 in the field member 219, so that the sleeve 2M is givensupport at its inner end to give it additional strength, as the journalmeans for the shaft 2I'2. Adjacent the aperture 2%, the coil pring 233cooperates with the outer surface of the field member an; so as toresiliently hold the field member are in its cooperative relation withthe boss 2% of the frame member 265.

The field member 2H5 is provided with a rear wardly-bent lug 2% whichcooperates with a forwardly-struck lug see, as shown in Fig. 10, on thespeed cup 263 to form a stop member for predetermining the zero positionof the pointer 25% as biased by means of the hair spring 2%. The zeroposition is conveniently determined by rotating the field mein "er 2H!on the boss 375 so as to determine the touching relation between thelugs 298' and 36!) on their respective members.

As has already been pointed out, the pointer shaft 2 i2 journaled intube or sleeve 2M which has already been described as being fixedlyattached (capable of adjustment) to bridge memher 282 in predeterminedconcentric relation with the shaft 2% 2 and the motor shaft 284. Thesleeve 2319. is provided with small internally positioned bearingsleeves at its forward and rear ends which are preferably made of Germansilver and are conveniently positioned in the bore of the sleeve 2M by apress fit. The sleeves 382, ad'- jacent the ends of the sleeve 214, formthe main bearings for the shaft 2H3, which has fixedly positioned on itthe speed cup 268 and the pointer Elie. The shaft 252 has an inwardlyprojecting portion 353:3 with reference to the speed cup 288 whichterminates in a central, bore 386 of the shaft, res adjacent the magnet295.

is provided with a counter-bore 383 which forms a shoulder, againstwhich is positioneda disc of tungsten Sid held in position. by, meansof. a small sleeve 3(2, press fitted into the bore.

The bore,

306. The plate 31!! cooperates with the rounded end; face of theprojection 304 to form an end thrust bearing for the pointer assemblypositioned on the, shaft2i2; The internal dimension of. thesleeve 3l2'is substantially larger than the external dimension of the shaft fittedtherein, so that the shaft will be entirely free from the eifects ofeccentricities of the shaft 2%. However, the plate 3U], coacting withthe end of the projection 364 of the shaft 2l2, tends to allow a slightmovement of the shaft 2J2 including the pointer assembly, whereby theobserver is given the, impression that the pointer and its mechanism isin operative condition.

As has been already pointed out in the description above, the twoodometers 238 are mounted on shaft 242 and 244 which are held in spacedparallel relation in abutments 284 and 285 formed on the forward face ofthe frame member 255. The abutment 266 is provided with apertures-3l4and 3 l 6 in which are journaled one end of shafts 244 and 262respectively. This is best shown in Fig. 3, a plan view. Abutment 22a isprovided with laterally opening slots 3H3 and 326 in which arepositioned the opposite ends of the shafts M2 and 2M. Adjacent theseends of the shafts 2 52 and 2 54 annular slots 322 are provided, one ineach shaft which is coincident with and inwardly extending from theinner side of the abutment 2%, as is most clearly shown in Fig. 3.

A spring member 32d, shown in perspective in Fig. 9, is provided tocooperate with the annular slots 322' by means of transversely extendingslots 525 and 323, formed on the upper side of the laterally extendingarm of the spring member which is, provided adjacent a central positionwith a fulcrum spring member see which rests against the upper surfaceof the field mem ber 2H3 and the inner wall of the abutment as is mostclearly shown in Fig. 5, thence extends upwardly to contact the lowerside of the ridge member 232, which it parallels for a short distance byits flattened portion Thence the spring member 324 bends downwardly atright angles, to cooperate with the inner face of theabutment 23.4, sothat the slots and 328 are positioned in the annular slots are of theshafts. 262 and 24s. The spring is adjusted in a manner to create anupward thrust against the shafts. and, due to the fact that the slots325 and 328 open transversely to the slots tit and 328 of the abutment2%, the ends of the shafts 242 and M15 are held in operative position,firmly supported in the abutment 284. Should, however, an operatordesire to remove the odometers from the abutments tiland 285, he mayreadily do so by pushing downwardly upon the cross member of the spring324 to release the slots 32 3 from the annular slots 322 in the ends ofthe shafts. This will allow removal of the shaft from the slots M8 and32d and can thus be completely removed by disengaging the opposite endsof the shafts from the apertures 5M 3.49 in the abutment 2853. Thisprovides a convenient and, at the same time, secure means for holdingthe odometer shafts in operative position in the abutments 284 and 286forming a part of frame member 2%.

The face-plate M8 is conveniently held in fixed relation to the assemblyby means of a taching screws 33% (Fig. 2) which are threaded into,pillars 33%; (Fig. 5), riveted on to the forward face; of bridge member282. The glass 7 face-plate me, already described hereinbefore,cooperates with a bezel on the forward end of an enclosing housing Mil,being held together by means of a ring Mil, as is well known the art andneed not be described in further detail. The housing 34-0 completelyencloses the recording apparatus hereinbefore described, and

is attached to the outer surface of the frame member 265 by means ofscrew 344 which is threaded into an aperture therein in an overlappingportion, as is most clearly shown in The construction of the odometers238 and their driving means is conventional other than already describedand will not be described in further detail.

It is to be understood that the above detailed description of thepresent invention is intended to disclose an embodiment thereof to thoseskilled in art, but that the invention is not to be construed as limitedin its application to the details of construction and arrangement ofparts illustrated in the accompanying drawings, since the invention iscapable of being practiced and carried out in various way withoutdeparting from the spirit of the invention. The language used in thespecification relating to the operation and function of the elements ofthe invention is employed for purposes of description and not oflimitation, and it is not intended to limit the scope of the followingclaims beyond the reuirements of the prior art.

What is claimed:

1. In an indicating device, a frame member, a driven shaft journaled insaid frame member for rotation therein, a hollow forwardly extendingboss on the frame member concentric with the shaft, a magnet mountedtransversely on said shaft and rotatable therewith within the hollowboss, a cup-lil e field member of magnetic material having its lipmounted in cooperative relation with said forwardly extending boss of adimension to cooperate with the rotating magnet through a narrow airgap, an eddy-current drag cup of non-magnetic material positioned torotate inside of the field member in the air gap between the fieldmember and the rotating magnet, a mounting shaft for said drag cupcoaxial with the first driven shaft and in contacting relation therewithadjacent the rotating magnet, forwardly extending lugs positioned on theframe member, a bridge member attached to and extending acros said lugs,a searing sleeve adjustably attached to said bridge and concentric withthe secondary shaft and extending into said field member for cooperationtherewith, bearing inserts in said sleeve for iournaling said secondaryshaft, a helical spring mounted externally of said sleeve andcooperating with the exterior of said field member to hold the fieldmember by tension against boss, a hair spring mounted on said bridgemember biasing said secondary shaft against the direction of rotation ofsaid magnet, stop means on the field cup for determining the zeroposition of secondary shaft as biased by the hair spring, and a pointercooperating with said secondary shaft.

2. In a device of the class described, a base member, a rotatable shafttransversely journaled in the base member, a mounting boss on the baseconcentric with the shaft, a pair of pillars on the base member, abridge member attached to the pillars in parallel relation with thebase, a

permanent magnet attached to the rotatable shaft, an eddy current cupwith a concentric shaft cooperating with the magnet, journal means forthe concentric shaft of the cup comprising a sleeve adjustably threadedinto the bridge concentric with the first shaft, a cupshaped fieldmember of magnetic material hav ing its lip fitted to the mounting bossexteriorly of the eddy current cup, the base of the field member havingan aperture to cooperate with the adjustable sleeve, a helical spring onthe sleeve anchored thereon at one end having its free end actingagainst the base of the field member to resiliently urge the fieldmember against the mounting boss, a spring to bias the eddy current cupto a zero position stop and a pointer to indicate the angulardisplacement of the speed cup against the bias of the spring created bythe eddy currents in the cup due to the rotation of the magnet.

3. In a magnetic speedometer, a rotating means including a polarizedmagnetic means, an eddycurrent means cooperating with the rotating meansto be rotatably influenced by the magnetic means against a bias forreturn to zero position, a pointer shaft on the eddy-current meansconcentrically rotatable by the eddy-current means under the influenceof the rotating means, said shaft being in touching relation with therotating means only at one end face, and spaced non-rotative bearingmeans for the pointer shaft at one side of the eddy-current means distalfrom the rotating means.

4. In a magnetic speedometer, a rotating means rotatable at a speed inproportion to the velocity of a vehicle, said rotating means including apolarized magnetic means, an eddy-current means cooperating with therotating means through the magnetic field of the magnetic means to berotatably influenced by the rotation of said magnetic means, a shaft formounting the eddycurrent means concentric with the rotating means and intouching relation therewith at only one end face, means active on saidshaft to bias the eddy-current means to the zero position, and a pair ofspaced non-rotative bearing means for the shaft positioned on one sideof the eddycurrent means.

5. In a magnetic speedometer, a rotating means including a polarizedmagnetic means, an eddy-current means cooperating with the rotatingmeans through an air gap to be rotatably influenced by the magneticfield of the magnetic means, a pointer shaft on the eddy-current meansto mount the eddy-current means for rotation on an axis concentric withthe axis of rotation of the rotating means, said shaft projecting intocooperative touching relation with the rotating means at only one of itsend faces, sleeve means adjustably mounted concentric with the pointershaft, a pair of spaced bearing means in said sleeve for rotatablymounting said pointer shaft, and means to bias the pointer shaft and theeddycurrent means to a zero position.

6. In a magnetic speedometer, a driven rotating means including apolarized magnetic means, an eddy-current means of non n'iagneticmaterial cooperating with the rotating means by an air gap to berotatably influenced by the magnetic field of the magnetic means againsta bias for return to zero position, a pointer shaft for re tatablymounting the eddy-current means concentrically with the rotating means,said shaft being in touching relation with the rotating means only atone end face, and spaced non-ro- 9 tative bearing means for the pointershaft on one side of the eddy-current means.

7. In a magnetic speedometer, a rotating means rotatable at a speed inproportion to the velocity of a vehicle said rotating means includapolarized magnetic means with a magnetic return, and eddy-current meansof non-magnetic material cooperating with the rotating means in themagnetic field created by the magnetic means to be rotatably influencedby the rotation thereof, a shaft for mounting the eddy-current meansconcentric with the rotating means said. shaft being in touchingrelation therewith only at one end face, means active on said shaft tobias the eddy-current means to the zero position, and spacednon-rotative bearing means for the shaft of the eddy-current meansforwardly from the rotating means.

8. The device defined in claim 2 further characterized by the end faceof the concentric shaft of the eddy-current cup being in touchingrelation with the rotatable shaft.

9. In a device of the class described, a nonmagnetic base member, arotatable shaft transversely journaled in the base member, permanentmagnet means mounted on the rotatable shaft and adapted to be rotatedthereby, a cup-shaped field member of magnetic material cooperating withthe magnet means and having its lip mounted on the base member inconcentric relation with the rotatable shaft, an eddy-current cup with aconcentric shaft cooperating with the magnet means and the field member,journal means for the concentric shaft of the eddy-current cupcomprising a sleeve longitudinally adjustable with reference to the basemember and fitted into a central aperture of the field member, mountingmeans for the sleeve including the concentric shaft with reference tothe base mem ber, a helical spring cooperating with the sleeve beinganchored at one end and acting at its other end against the base of thefield member to resiliently urge the lip of the field member against thebase member, and a spring to bias the eddy-current cup against rotationin one direction.

10. The device defined in claim 9 further characterized by a touchingrelation between the end face of the concentric shaft of theeddy-current cup and the rotatable shaft mounting the magnet means.

WILLIAM MCCANDLESS.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,371,096 Howe et a1. Mar. 8, 1921 1,597,691 Olsen Aug. 31,1926 1,670,836 Berge May 22, 1928 1,808,198 Zubaty June 2, 19311,933,086 Bottegay Oct. 31, 1933 1,962,538 Toney June 12, 1934 1,984,082Read Dec. 11, 1934 2,027,589 Helgeby Jan. 14, 1936 2,046,163 HelgebyJune 30, 1936 2,211,543 Kollsman Aug. 13, 1940 2,232,789 Kollsman Feb.25, 1941 2,263,264 Duwe Nov. 18, 1941 2,273,848 Ely et al. Feb. 24, 19422,339,743 Norman Jan. 18, 1944

